There are LCDs and projection screens provided with a light-diffusing sheet to enable viewers to view images from angles in a wide angular range.
As an example of the Light-diffusing sheet, a lenticular sheet having a surface provided with semicylindrical lenticules arranged parallel on a plane, and a sheet formed of resins respectively having different refractive indices are disclosed in, for example, JP 2003-504691 A (Patent document 1). In some cases, this lenticular sheet and this sheet are used in combination.
When the lenticular sheet having unflat surface is attached to the surface of the screen of an LCD with an adhesive, inequalities of the surface of the lenticular sheet are filled up with the adhesive. In most cases, the respective refractive indices of the material forming the lenticular sheet and the adhesive do not differ greatly from each other. Consequently, the light diffusing effect on the basis of the inequality of the surface of the lenticular sheet is nullified.
A resin having a high refractive index and a resin having a low refractive index are expensive. When it is desired to form a light-diffusing sheet capable of diffusing incident light in a wide angular range, at least one of materials forming the light-diffusing sheet is inevitably an expensive resin and, consequently, the manufacturing cost of the light-diffusing sheet is high.